The recent trends toward early detection, image-guided surgery, and preference for minimally invasive treatments for prostate cancer have fostered continuing interest in cryotherapeutic approaches to prostate cancer. Cryosurgical treatment has fallen in and out of favor, due at least in part to the risk of damage to sensitive tissues in the urethra and rectal wall. The availability of transrectal ultrasound and urethral warmers improves the situation markedly, but the shape of the freeze zone remains challenging to control. The proposed cryosurgical probe provides direct control over the shape of the frozen region, protecting sensitive nearby tissues from thermal damage. It also includes sensors to measure the actual temperatures achieved across the freeze zone. In Phase I, a proof-of-principle probe will be fabricated and tested in vitro. In Phase II, a prototype probe will be built and tested in vivo. PROPOSED COMMERCIAL APPLICATIONS: The proposed cryotherapy probe has strong commercial potential. Our commercialization strategy is based on licensing the technology developed under this program to an existing vendor of medical equipment.